Device Payment Plan Agreement and Wireless Service Receivables - Schedule of Device Payment Plan Receivables, Net (Detail) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Receivables [Abstract]
Device payment plan agreement receivables, gross	$ 31,308	$ 29,206
Unamortized imputed interest	(975)	(758)
Device payment plan agreement receivables, at amortized cost	30,333	28,448
Allowance	(1,315)	(1,151)
Device payment plan agreement receivables, net	29,018	27,297
Accounts receivable, net	15,141	13,173
Other assets	$ 13,877	$ 14,124